Variable speed drive (VFD) systems, such as those that may be employed in association with motors, fans and compressors, often by necessity must pass through frequencies that excite structural resonances. The resonances can lead to structural failure of motor bearings, fan supports and refrigerant piping, customer complaints about excessive vibration, or excessive noise.
Many variable speed motor applications accomplished by a VFD are prone to vibration problems within the desired speed range due to resonances and critical speeds. Products that may be adversely impacted include, without limitation, fans, motors, refrigeration compressors and air compressors.